The outer skin layer (epidermis) forms a natural barrier to harmful substances from entering the body from the outside world. However, both hydrophilic and hydrophobic substances, including substances harmful to the body, are capable of penetrating across the stratum corneum layer into the viable skin tissues. Additionally, when the skin is compromised by cuts, abrasions, rashes, and the like, infectious agents such as viruses or bacteria may more readily enter the body. Finally, the skin may itself be harmed by commonly used noxious agents, for example toxic chemicals used in the laboratory, in industry, and at home.
One method commonly used to protect skin against harmful substances is, of course, the wearing of latex or rubber gloves. However, in general gloves are uncomfortable to wear for extended periods of time because of perspiration build-up, they reduce tactile sensitivity, and gloves are themselves quite susceptible to tearing, formation of pinholes, etc., with the consequent breakdown of protection.
The foregoing discussion is addressed largely to the protection of the hands, but can equally apply to other areas of the body, in particular the face, which is another area for which protection is often sought. The conventional mode of protection for the face is a mask, for example a plastic face mask. However, wearing a mask is uncomfortable because of perspiration build-up, and tends to diminish clarity and scope of vision. There are also occasions when the whole body may need protection from exposure to harmful substances, and in these situations protective body suits are worn. Such body suits incorporate all of the disadvantages of gloves or face mask mentioned above.
It would therefore be advantageous to have a means of protecting skin from harmful substances that does not require the use of gloves, face masks, or whole body suits. Such a means of protection should guard against toxic substances harmful to the skin itself, and substances capable of penetrating the skin barrier, such as viruses, bacteria, parasites, poisonous gases, toxic agents such as pesticides and herbicides, agents used as chemical weapons, for example mustard gases or neurotoxic agents, chemicals, and the like. The skin protectant should be simple and uncomplicated to apply, and not easily removed by water and aqueous environments. Greater skin protection would be provided if the protecting agent not only formed a barrier on the skin surface, but also was absorbed into the outer layer of the skin, i.e. the stratum corneum itself. Its presence in the stratum corneum would enhance efficiency as well as duration of action, in part due to the increased resistance to removal by friction or wiping. In this manner, a durable barrier would be formed that is not easily removed inadvertently or by solvents. Clearly this would be desirable, because in this manner the protective barrier function of the stratum cornea itself would be enhanced, and the barrier would not merely form a thin layer above the skin surface.